Heat exchangers of the tube-fin type are well known in the prior art. Such heat exchangers are particularly well adapted for use as automobile oil coolers because of their light weight and compact size. The fin configuration is of extreme importance for promoting an efficient transfer of heat from the hot fluid to the cooling fluid. Several prior art assemblies disclose different fin configurations, all of which are directed toward the same result: breaking up the boundary layer of hot fluid across the fin to promote turbulence which results in greater heat transfer.
The U.S. Pat. No. 4,300,629 to Hatada et al discloses a tube-type heat exchanger. The fins have a plurality of louver elements thereon. These louver elements are of different heights so that the edges thereof are offset in the direction orthogonal to the plane of the fin. This pattern is for promoting turbulence and more efficient heat transfer.
The U.S. Pat. No. 4,550,776 to Lu issued Nov. 5, 1985 discloses another fin design for use in a tube-fin type heat exchanger. The fin has a plurality of louver groups thereon. The louver groups extend radially from each of the tube openings toward the next adjacent tube opening in each of six directions. The lower groups are arranged in such a manner as to promote mixing in only one direction. That is, the flow is only directed toward one side of the fin. In such an arrangement the flow is not mixed in a lateral direction. Additionally, the crests of the louvers comprise openings and are not interconnected. This reduces the amount of surface area available for heat transfer from the fluid passing over the fin.
The U.S. Pat. No. 2,360,123 to Gerstung et al issued Oct. 10, 1944 discloses an oil cooler. The oil cooler includes a plurality of tubes through which hot fluid passes. Extending within the tubes are corrugated sheets. The crests of the corrugations are bonded to the tubes through which the hot fluid passes. Because the crests are bonded to the tubes, they become integral therewith. This eliminates the crests as in available heat transfer surface. Thus, only the portions between crests are available as a heat transfer surface.